main: Temporary fix assertion error

This variant uses `fdopen()` which is not standard, but it fixes problem on my 
system. In next commit `scriptin` will use `FileDescriptor*` from os/fileio in 
place of `FILE*`.

2 files changed, 64 insertions, 0 deletions

diff --git a/test/functional/core/main_spec.lua b/test/functional/core/main_spec.lua
index c3aeb30398..bad5d72142 100644
--- a/test/functional/core/main_spec.lua
+++ b/test/functional/core/main_spec.lua
@@ -1,7 +1,9 @@
 local lfs = require('lfs')
 local helpers = require('test.functional.helpers')(after_each)
+local Screen = require('test.functional.ui.screen')
 
 local eq = helpers.eq
+local feed = helpers.feed
 local clear = helpers.clear
 local funcs = helpers.funcs
 local nvim_prog = helpers.nvim_prog
@@ -53,5 +55,51 @@ describe('Command-line option', function()
       local attrs = lfs.attributes(fname)
       eq(#('100500\n'), attrs.size)
     end)
+    it('does not crash after reading from stdin in non-headless mode', function()
+      local screen = Screen.new(40, 8)
+      screen:attach()
+      eq(nil, lfs.attributes(fname))
+      funcs.termopen({
+        nvim_prog_abs(), '-u', 'NONE', '-i', 'NONE',
+         '--cmd', 'set noswapfile shortmess+=IFW fileformats=unix',
+         '-s', '-'
+      })
+      screen:expect([[
+        ^                                        |
+        {1:~                                       }|
+        {1:~                                       }|
+        {1:~                                       }|
+        {1:~                                       }|
+        {2:[No Name]             0,0-1          All}|
+                                                |
+                                                |
+      ]], {
+        [1] = {foreground = 4210943, special = Screen.colors.Grey0},
+        [2] = {special = Screen.colors.Grey0, bold = true, reverse = true}
+      })
+      feed('i:cq<CR><C-\\><C-n>')
+      screen:expect([[
+        ^                                        |
+        [Process exited 1]                      |
+                                                |
+                                                |
+                                                |
+                                                |
+                                                |
+                                                |
+      ]])
+      --[=[ Example of incorrect output:
+      screen:expect([[
+        ^nvim: /var/tmp/portage/dev-libs/libuv-1.|
+        10.2/work/libuv-1.10.2/src/unix/core.c:5|
+        19: uv__close: Assertion `fd > STDERR_FI|
+        LENO' failed.                           |
+                                                |
+        [Process exited 6]                      |
+                                                |
+                                                |
+      ]])
+      ]=]
+    end)
   end)
 end)
diff --git a/test/unit/os/fs_spec.lua b/test/unit/os/fs_spec.lua
index 860ebfdbcb..b03040260f 100644
--- a/test/unit/os/fs_spec.lua
+++ b/test/unit/os/fs_spec.lua
@@ -483,6 +483,22 @@ describe('fs function', function()
       end)
     end)
 
+    describe('os_dup', function()
+      itp('returns new file descriptor', function()
+        local dup0 = fs.os_dup(0)
+        local dup1 = fs.os_dup(1)
+        local dup2 = fs.os_dup(2)
+        local tbl = {[0]=true, [1]=true, [2]=true,
+                     [tonumber(dup0)]=true, [tonumber(dup1)]=true,
+                     [tonumber(dup2)]=true}
+        local i = 0
+        for _, _ in pairs(tbl) do
+          i = i + 1
+        end
+        eq(i, 6)  -- All fds must be unique
+      end)
+    end)
+
     describe('os_open', function()
       local new_file = 'test_new_file'
       local existing_file = 'unit-test-directory/test_existing.file'